Today I will show you three java examples that copy the source directory with it’s content to the target directory.
1. Use Java IO To Copy Directory.
- This example uses the traditional java File and Input / Output Stream class to implement the copy directory process. You can see code comments for more detail.
public void copyDirectory(String srcDir, String destDir) { try { // Create source object. File srcDirFile = new File(srcDir); // Create destination object. File destDirFile = new File(destDir); /* Only copy exist directory. */ if(srcDirFile.exists()) { if(srcDirFile.isDirectory()) { /* If destination directory is not exist then create it. */ if(!destDirFile.exists()) { destDirFile.mkdirs(); System.out.println("Target Directory " + destDirFile + " dose not exist, create it."); } /* Get source directory sub-content. */ File[] srcDirSubFileArr = srcDirFile.listFiles(); /* Loop in the directory sub content. */ for(File srcDirSubFile : srcDirSubFileArr) { /* Get subfile name. */ String subFileName = srcDirSubFile.getName(); /* Create source subfile and target subfile. */ File subSrcFile = new File(srcDirFile, subFileName); File subDestFile = new File(destDirFile, subFileName); /* Copy recursively. */ copyDirectory(subSrcFile.getCanonicalPath(), subDestFile.getCanonicalPath()); System.out.println("Recursive copy from " + subSrcFile.getCanonicalPath() + " to " + subDestFile.getCanonicalPath()); } }else { /* If source is a file. */ this.copyFile(srcDirFile, destDirFile); } } }catch(Exception ex) { ex.printStackTrace(); } } /* Copy data from source to target. * */ public void copyFile(File srcFile, File destFile) throws IOException { /* Create buffered input stream to improve read speed. */ InputStream srcInput = new FileInputStream(srcFile); BufferedInputStream srcBis = new BufferedInputStream(srcInput); /* Create buffered output stream to improve write speed. */ OutputStream destOutput = new FileOutputStream(destFile); BufferedOutputStream destBos = new BufferedOutputStream(destOutput); byte byteBufferArr[] = new byte[1024]; /* Read byte data to buffer, if all data has been read then readLen==-1. */ int readLen = srcBis.read(byteBufferArr); while(readLen>0) { destBos.write(byteBufferArr); readLen = srcBis.read(byteBufferArr); } /* Do not forget flush output stream buffer and close both input and output buffer stream.*/ destBos.flush(); destBos.close(); destOutput.close(); srcBis.close(); srcInput.close(); System.out.println("Copy successful from " + srcFile.getCanonicalPath() + " to " + destFile.getCanonicalPath()); }
2. Use Apache Commons IO.
- Go to Apache commons-io download page.
- Download the latest version.
- After download, extract the zip file to a local folder. Then add commons-io-2.5.jar to your java project as below. You can read How to add selenium server standalone jar into your java project to learn how to add a jar in the java project.
- Java example code.
/* Use Apache commons io to copy directory. * srcDirPath : Source folder path. * destDirPath : Target folder path. * fileExtension : If empty then copy all, if specified then only copy those extension file, such as "exe", "txt" etc. * */ public void copyWithApacheCommonsIO(String srcDirPath, String destDirPath, String fileExtension) { try { File srcDir = new File(srcDirPath); File destDir = new File(destDirPath); if("".equals(fileExtension)) { /* Copy all. */ /* Will create destDir automatically if destDir dose not exist. */ FileUtils.copyDirectory(srcDir, destDir); }else { /* Copy special extension file. */ /* Create a special extension filter.*/ IOFileFilter fileExtensionFilter = FileFilterUtils.suffixFileFilter(fileExtension); /* Use and(IOFileFilter ... fileFilter) method to declare a filter that only copy those extension file, such as "exe", "txt". * The and method three-dot means the method parameter can be zero or more IOFileFilter object, or a IOFileFilter array. * */ IOFileFilter fileFilter = FileFilterUtils.and(FileFileFilter.FILE, fileExtensionFilter); /* Use or(IOFileFilter ... fileFilter) method to tell FileUtils copy either directory or specified extension file just created. */ FileFilter fileAndDirFilter = FileFilterUtils.or(DirectoryFileFilter.DIRECTORY, fileFilter); // Copy using the filter FileUtils.copyDirectory(srcDir, destDir, fileAndDirFilter); } System.out.println(srcDirPath + " has been copied to " + destDirPath + " successfully. "); }catch(Exception ex) { ex.printStackTrace(); } }
3. Use Java New IO.
- Create a File visitor class first, this visitor will be invoked during java new io’s
Files.walkFileTree()method. The below file JavaNewIOCopyFileVisitor.java is an example.public class JavaNewIOCopyFileVisitor extends SimpleFileVisitor { private String srcDir; private String destDir; public String getSrcDir() { return srcDir; } public void setSrcDir(String srcDir) { this.srcDir = srcDir; } public String getDestDir() { return destDir; } public void setDestDir(String destDir) { this.destDir = destDir; } @Override public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes arg1) throws IOException { /* Get both source and destination directory Path object. */ Path srcPath = Paths.get(this.getSrcDir()); Path destPath = Paths.get(this.getDestDir()); /* Get the relative Path object between source and current directory. */ Path relativePath = srcPath.relativize(dir); /* Get the target directory Path instance. */ Path targetDirPath = destPath.resolve(relativePath); try { /* Copy current go through directory to target directory, replace target if exist. */ Files.copy(dir, targetDirPath, StandardCopyOption.REPLACE_EXISTING); } catch (FileAlreadyExistsException ex) { if (!Files.isDirectory(targetDirPath)) throw ex; } return FileVisitResult.CONTINUE; } @Override public FileVisitResult visitFile(Path file, BasicFileAttributes arg1) throws IOException { /* Get both source and destination directory Path object. */ Path srcPath = Paths.get(this.getSrcDir()); Path destPath = Paths.get(this.getDestDir()); /* Get Path object that current file relative to source folder. */ Path relativeFilePath = srcPath.relativize(file); /* Use the relative path to get target folder Path object. */ Path targetFilePath = destPath.resolve(relativeFilePath); /* Copy current file to target file, replace target if exist. */ Files.copy(file, targetFilePath, StandardCopyOption.REPLACE_EXISTING); return FileVisitResult.CONTINUE; } } - Copy use java new io code example.
/* Copy source directory to target directory use java new io. */ public void copyWithJavaNewIO(String srcDir, String destDir) { try { /* First create a file visitor object which will be invoked when go through each file or directory. */ JavaNewIOCopyFileVisitor copyFileVisitor = new JavaNewIOCopyFileVisitor(); copyFileVisitor.setSrcDir(srcDir); copyFileVisitor.setDestDir(destDir); /* Create the root copy Path object. */ Path srcPath = Paths.get(srcDir); /* Walk through each file or directory under the root path.*/ Files.walkFileTree(srcPath, copyFileVisitor); System.out.println(srcDir + " has been copied to " + destDir + " successfully. "); }catch(Exception ex) { ex.printStackTrace(); } }
4. Difference Between Java IO and Apache Commons IO.
- Apache Commons IO provides more useful classes with advanced features.
- Apache Commons IO and Java IO copy speed are not too much different.
- Below is the java main method, we have record the two copy methods used time. The source directory is about 4 Gigabyte, we can see two methods used time is nearly the same.
public static void main(String[] args) { CopyDirectoryExample cde = new CopyDirectoryExample(); /* Below code will copy only .exe file from source to target folder. */ cde.copyWithApacheCommonsIO("C:/WorkSpace/DreamWeaver", "C:/WorkSpace/DreamWeaver_bak", "exe"); long startTime = 0; long endTime = 0; startTime = System.currentTimeMillis(); cde.copyDirectory("C:/WorkSpace/dev2qa.com", "C:/WorkSpace/dev2qa.com_bak_1"); endTime = System.currentTimeMillis(); long deltaTime = endTime - startTime; System.out.println("copyDirectory(String srcDir, String destDir) use time " + deltaTime); startTime = System.currentTimeMillis(); cde.copyWithApacheCommonsIO("C:/WorkSpace/dev2qa.com", "C:/WorkSpace/dev2qa.com_bak_2", ""); endTime = System.currentTimeMillis(); deltaTime = endTime - startTime; System.out.println("copyWithApacheCommonsIO(String srcDir, String destDir) use time " + deltaTime); startTime = System.currentTimeMillis(); cde.copyWithJavaNewIO("C:/WorkSpace/dev2qa.com", "C:/WorkSpace/dev2qa.com_bak_nio"); endTime = System.currentTimeMillis(); deltaTime = endTime - startTime; System.out.println("copyWithJavaNewIO(String srcDir, String destDir) use time " + deltaTime); } - Below are the two methods copyDirectory(String srcDir, String destDir) and copyWithApacheCommonsIO(String srcDir, String destDir) used time comparison.
Recursive copy from C:\WorkSpace\dev2qa.com\Zhao Song English_Resume.doc to C:\WorkSpace\dev2.com\Zhao Song English_Resume_1.doc copyDirectory(String srcDir, String destDir) use time 396303 C:\WorkSpace\dev2qa.com has been copiea to C:\WorkSpace\dev2qa.com_bak_2 successfully. copyWithApacheCommonsIO(String srcDir, String destDir) use time 390880
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